From Alverson Software:
ZTerm is a terminal emulation program for the Macintosh. In its day, many people used it to connect to Bulletin Board Systems and download files. Now we have the Internet. ZTerm is still a useful utility for those systems that offer only dial-up connections and for connecting to devices through a serial port, as do many routers. For newer Macs that don't have a normal serial port, ZTerm can talk to ports on USB to serial adapters, through the appropriate driver software supplied with the adapter. New features is version 1.1 include separate versions for Mac OS 8/9 and Mac OS X and the addition of an appearance manager and navigation services. The OS X version gets a list of serial ports from IORegistry.